Removal of iron contaminants from hydrocarbon oils



United States Patent US. Cl. 208-252 9 Claims ABSTRACT OF THE DISCLOSURE A process for the selective removal of iron from ironcontaminated oils by contacting the oils with dilute sulfuric acid, containing 0.1- weight percent H 80 Other metals in the oils are essentially unaffected by the acid.

Background of the invention This invention relates to the removal of metallic contaminants from hydrocarbon oils and, in particular, to the removal of iron contaminants therefrom.

In catalytic cracking, it has been known for some time that certain metals, particularly iron, nickel and vanadium, are very harmful to cracking catalysts. When deposited on cracking catalysts in concentrations of about 0.1% or less, such metals cause the production of excessive amounts of coke and gas at the expense of valuable gasoline and heating oil fractions. This leads to an overloading of the regeneration and gas handling equipment and reduces the allowable feed rate to the catalytic cracking units. Iron has been found to be a particularly detrimental contaminant, not only in catalytic cracking, but also in other catalytic processes such as hydrocracking.

This iron is brought into a catalytic unit, along with the other unfilterable metallic impurities, such as nickel and vanadium, with the feedstock in the form of metalloorganic compounds. It is the removal of these iron contaminants with which the present invention is concerned.

It has previously been known that iron, nickel, vanadium and other metals could be removed from oils by using concentrated sulfuric acid. More recently, it was disclosed in US. Patent No. 2,778,777 that sulfuric acid concentrations as low as weight percent H 80 would also effect removal of these metals. However, in the past it has been believed that acid concentrations below 10% would be ineffective for promoting substantial metals Patented Apr. 1, 1969 prior art, will effect substantial iron removal from ironcontaminated oils. This process appears to be specific to iron removal, for other metals in metals-contaminated oils are substantially unaffected by acids of these extremely low concentrations.

Summary The process of this invention is a process for removing iron from metals-containing hydrocarbon oils while leaving the content of the oil of metals other than iron substantially unchanged. Basically, the process involves contacting the oil with aqueous sulfuric acid in a concentration of 0.l-5 Weight percent H followed by separating the iron-free oil from the aqueous acid phase to which the iron has been transferred.

Detailed description of the invention In its broadest form, the process of this invention comprises contacting the iron-contaminated oil with dilute, aqueous sulfuric acid having a concentration of 0.1-5 weight percent H 50 followed by separation of the ironfree oil from the aqueous phase to which the iron has been transferred.

In a preferred embodiment, the temperature at which the contacting takes place is in a range of -50'O F.

In a more preferred embodiment, the temperature at which the contacting takes place is in the range of 225 F.

In another preferred embodiment, the acid concentration is between 0.1 and 1.0 weight percent H 80 Contacting time may be between one minute and two hours.

The hydrocarbon oil/aqueous acid weight ratio may range from 0.05 :1 to 5:1, depending upon the iron content of the hydrocarbon oil and the acid content of the aqueous phase. If desired, a light hydrocarbon diluent may be added to the oil to reduce its viscosity and facilitate contacting of the acid and oil. The amount of diluent used may be any amount necessary to reduce the viscosity of the oil to the desired viscosity for contacting. In general, this amount will be approximately one volume of diluent per volume of oil, although in the case of highly viscous oils, several volumes of diluent per volume of oil may be used.

Table I illustrates the significant amount of iron removal which is obtainable by this process. It will be noted from the data that, at lower temperatures, the iron removal is decreased.

TABLE I Run No.

Type of Oil Crude Gas 011 Gas oil Deasphalted Deasphalted Deasphalted White oil oil oil oil Acid cgncentration, wt. percent 5 5 1 5 5 5 0. 0

4 Temperature, F 195-205 210 -210 160490 74 -195 210-215 Contacting time, min 60 60 10 15 15 15 15 Oil/acid, wtJwt 2. 5:1 2. 5:1 2. 5:1 0.511 0. 5:1 0. 5:1 1:1 Diluent None None None Toluene Toluene Toluene None Oil/diluent, vol./vol 1:1 1: 1 1: 1 Deduction of iron content,

percent. 99 82. 5 91 76 54 74 97 removal. This has been, in fact, shown to be true in the case of nickel and vanadium.

Table II illustrates the fact that this process is essentially specific to iron removal. The data show that, while It has now been discovered, however, that sulfuric acid 65 most of the iron was removed from a typical feed, very concentrations which are one or two orders of magnitude less concentrated than those heretofore known to the little of the nickel, vanadium, or sodium also present in metals contaminated oil was removed.

3 TABLE II Feed: Deasphalted oil Acid concentration, weight percent H 50 5 Metals reduction, weight percent:

Iron "a- 76 Nickel 12 Vanadium 15 Sodium 12 The above examples are given for illustrative purposes only. It is apparent that many widely difierent embodiments of this invention may be made without departing from the scope and spirit thereof, and, therefore, it is not intended to be limited except as indicated in the appended claims.

I claim:

1. A process for the removal of iron contaminants from an iron-contaminated hydrocarbon oil which comprises contacting the oil with aqueous sulfuric acid in a concentration of 0.1-5 weight percent H 80 separating the resulting oil having a reduced iron content from the iron-containing aqueous acid phase and recovering said resulting oil.

2. The process of claim 1 wherein the contacting temperature is in the range of 100500 F.

3. The process of claim 2 wherein the temperature is in the range of 150-225 F.

4. The process of claim 1 wherein the oil and the acid are contacted for between one minute and two hours.

5. The process of claim 1 wherein the aqueous sulfuric acid concentration is 0.1-1.0 weight percent H 6. The process of claim 5 wherein the contacting temperature is in the range of 500 F.

7. The process of claim 6 wherein the temperature is in the range of l50225 F.

8. The process of claim 5 wherein the oil and the acid are contacted for between one minute and two hours.

9. The process of claim 1 wherein the hydrocarbon oil contains other metallic contaminants in addition to iron, and the steps of contacting said hydrocarbon oil with said acid and separating said acid from said resulting oil, results in a selective removal of iron from said hydrocarbon oil with removal of only minor amounts of said other metallic contaminants.

References Cited UNITED STATES PATENTS 2,778,777 1/1957 Powell 196-440 DELBERT E. GANTZ, Primary Examiner.

J. D. MYERS, Assistant Examiner. 

